The invention concerns an apparatus for intermittently conveying packages which are conveyed in a first travel direction in package carriers on a first process plane in positions beneath various treatment stations and on a second return plane in a second travel direction parallel to the first travel direction, forming a conveyor circuit.
For producing and in particular finishing packages, in known machines they are held in workpiece carriers and intermittently fed by means of endlessly circulating conveyor belts to individual treatment stations in which the respective package for example is filled after having been folded into the finished condition, and finally closed. The conveyor belts pass around two direction-changing guide rollers, wherein the workpiece carriers are turned in the conveyor arcs thereof from a vertical orientation into a horizontal one and then again into a vertical orientation. The vertical orientation is that for the process plane because conveyors of that kind are frequently used in relation to the packaging of liquid foodstuffs which are introduced from above into the package which is disposed therebeneath and which is open upwardly. In many conveyors, the workpiece carriers are rigidly interlinked, for example by way of roller chains or link chains. This is found to suffer from the disadvantage that after prolonged operation there are undesirable increases in the length of the chains, with the consequence of inaccurate positioning under the respective treatment station. If there a wish to use such conveyors in the foodstuffs industry sterile packaging is frequently required and when using roller or link chains movable parts have to be lubricated so that such conveyors cannot operate in clean room conditions where however the operation of filling the packages is carried out.
Admittedly, operators have already changed over to using toothed belts in order to avoid lubrication and to have a smaller increase in length. However, separating off the package carriers, for example for the purposes of better sterilization, and subsequent refitment, are practically impossible. In addition, when using toothed belts there is often a limited level of resistance to thermal and chemical influences in the environment.
In order to increase the machine output of packaging machines and there in particular filling devices, that is to say in order to be able to process a larger number of packages in a machine per unit of time, a plurality of package carriers have been arranged in mutually juxtaposed relationship along the process plane, the package carriers therefore being arranged in mutually juxtaposed relationship transversely with respect to the first travel direction. If the endless conveyors of the known kind can be used at all for multiplication in respect of width, the width of such a process plane however, at least for static reasons, is subject to limits which do not permit a further increase in output.
Therefore the object of the invention is to provide a conveyor apparatus for packages of the kind set forth in greater detail in the opening part of this specification, which while being of a compact structure permits a high output and operation with simple devices.
In accordance with the invention that object is attained in that the respective mutually superposed ends of the substantially horizontally extending first conveyor in the first process plane and the substantially horizontally extending second conveyor in the second return plane are interconnected to form the conveyor circuit by substantially vertically operating second and fourth lift conveyors, that each conveyor has a separate drive, that arranged between the first process plane and the second return plane is a third loading plane, the three planes are substantially horizontally arranged, each package carrier is of a substantially flat structure which is held in a substantially horizontal position over the conveyor circuit and that provided in the region of the third loading plane are means for loading and unloading the packages into and/or out of the package carriers in a loading direction which is parallel to the first travel direction of the packages.
It is firstly possible to explain the conveyor apparatus according to the invention by means of a simple conveyor picture which shows a rectangular conveyor path with a first travel direction at the top on a first process plane which is adjoined at the end of that plane by a lift conveyor in order to convey the package carriers out of the first process plane downwardly into the second return plane; that is then followed by the substantially horizontally extending third conveyor in the second return plane, in which respect here the travel direction is parallel but opposite to that of the first process plane, and the conveyor circuit is closed by a so-called fourth lift conveyor which lifts the package carriers from the lower second return plane into the upper first process plane. If that rectangular path is viewed in the clockwise direction, then the package carriers are moved in the first process plane from left to right by the first conveyor, at the end they are lowered vertically downwardly by the second lift conveyor into the second return plane, there they are moved horizontally towards the left by the third conveyor so that the fourth lift conveyor can then again vertically lift the package carriers upwardly into the initial position into the first process plane. Different travel patterns can be set by virtue of the respectively separate drives for each of the conveyors. In addition it is possible to adopt very simple drives and the drives can be caused to operate at different speeds, in accordance with the respective control thereof, in such a way that for example a large number of package carriers is present in the entire conveyor circuit only on one of the horizontal planes, while in the other three conveyors only few to no package carriers are being moved. It is possible in that way to save on package carriers, simplify operation, for example afford excellent cleaning possibilities, and nonetheless predetermine a high level of output. The most slowly operating station predetermines the time cycle for intermittent conveyance of the packaging carriers.
The advantageously compact structure of the conveyor apparatus is not subjected to any limitation if the above-mentioned third loading plane is disposed between the first process plane and the second return plane. However by virtue of the arrangement of that loading plane, it is possible to considerably increase the output of the conveyor apparatus in that the loading and unloading operation can be accelerated to a surprisingly great degree, which was not possible in the case of the previous conveyors with the feed at the entry to the process plane being vertically downwardly. The overall structure is simplified by virtue of the fact that the three planes described are arranged substantially horizontally. In a preferred embodiment the length of the conveyor is determined by the various, successively arranged treatment stations or the overall length required for same. The height of the conveyor apparatus of compact structure is kept low and operation is speeded up and simplified because each substantially flat package carrier is always held horizontally, including in the vertically operating second and fourth lift conveyors. More specifically the loading and unloading means can then withdraw finished packages from the package carriers and introduce empty packages into the package carriers at the loading position, with a high level of acceleration and over short distances, in which respect that can be effected at the same time for a multiplicity of packages if the package carriers accommodate a plurality of packages.
The foregoing measures show how a very powerful conveyor can nonetheless be of a very compact structure and permits the use of simple devices for operation thereof, for example for the loading operation, for varying the travel direction, although or precisely because no arcuately guided route has to be followed or also there is not an arcuately guided portion of conveyor bodies that has to be moved.
In a further advantageous configuration of the invention the total conveyor time of the lift conveyor is substantially equal to the cycle time of the first conveyor in the first process plane and the time for loading or unloading is approximately equal to the transport time within the cycle time of the first conveyor. The intermittent movement of the first conveyor is effected in cycles each with a respective given cycle time. The duration of that cycle time is equal to the sum of the transport time plus the hold time. This means in other words that in one cycle a package carrier on the one hand is transported to a given treatment station (transport time) and on the other hand is additionally thereafter stopped until the treatment is concluded (hold time). The cycle time has expired, after the expiry of those two periods of time. The first conveyor in the first process plane has comparatively short transport times in relation to the hold times. The package carrier can therefore be transported to the new treatment station in a shorter time than the time required to conclude the treatment. If in a preferred embodiment the cycle time is six seconds, then the hold time can be set to five seconds and the transport time to one second. In accordance with the invention the conditions are correspondingly reversed in the lift conveyor. The time which is necessary to carry out the entire transportation procedure of the lift conveyor, that is to say the time for the movement and for the loading procedure (loading or unloading) is approximately as long as the cycle time of the first conveyor. Of that total cycle time the time for loading and unloading the lift conveyor represents only a fraction. The time for loading and unloading the lift conveyor is approximately equal to or less than the transport time of the first conveyor; in the above-indicated example therefore only about one second is needed for loading or unloading. That surprisingly short time is only possible because there is the separate third loading plane for the loading and unloading operations, the third loading plane being horizontal like the other two planes (process plane, return plane). Added to that is the fact that the loading and unloading means involve an operating direction which is parallel to the first travel direction of the packages. If the lift conveyor operates vertically then loading and unloading are effected in a horizontal direction. In the loading operation for example pushers only need to push the treated packages out of the package carriers and a short period of time is sufficient for that. A specific embodiment of a preferred machine with a particular conveyor apparatus according to the invention permitted loading and unloading of 1 liter packages in 0.8 seconds, and in another type of machine 0.5 seconds. No previously known machine permitted loading or unloading of a conveyor in such a short time.
It is further desirable in accordance with the invention if the package carrier has on two diametrally opposite sides U-shaped, outwardly open recesses which are oriented in the first travel direction of the first conveyor. A vertical axis can be envisaged in the center of a U. If an inverted further U is arranged at a spacing under that first U oriented in such a way that both central axes fall onto one line, then that gives the above-described orientation of the two recesses. In accordance therewith the invention also provides the teaching that said central line of the two U-shaped recesses which are arranged in mutually opposite relationship is parallel to the first travel direction. The orientation of those recesses has a particularly advantageous effect in the third loading plane in the loading and unloading operations. In the unloading procedure the one package is pushed or pulled out of the recess which is open outwardly in the conveyor direction, with that direction of movement being for example the same as that of the first travel direction. The other oppositely disposed package is then moved out in the opposite direction. Both are effected at the same time and require only little time. The other advantage of the two recesses is that in that way the package carrier has double the capacity. The man skilled in the art knows that the width of a machine and also a conveyor apparatus cannot be increased just as maybe desired because strength conditions impose a limit in terms of increasing the width of a package carrier. By virtue of the arrangement of two recesses which are oriented relative to each other, it is possible to hold, transport, load and unload two packages on this path, instead of one.
It is further desirable in accordance with the invention if the package carrier is in the configuration of an elongate bar extending transversely with respect to the first travel direction, in such a way that the recesses come to lie in pairs in mutually juxtaposed relationship. Besides the above-mentioned doubling of the capacity of a package carrier from one to two packages, the enlargement in capacity in a transverse direction is possible to a certain extent as is permitted by strength conditions. For that purpose the package carrier can be designed in a bar or plate form and the recesses can be arranged in paired mutually juxtaposed relationship. The loading and unloading devices which operate in the third loading plane can then move all mutually juxtaposed packages in a bar out or in at once. The capacity of such a conveyor apparatus is thereby considerably increased.
It is also advantageous in accordance with the invention if the package carrier for holding bottles is a bar-shaped metal sheet with pairs, arranged in mutually juxtaposed relationship transversely with respect to the first travel direction, of U-shaped recesses which face away from each other and the width of which corresponds to the outside diameter of the bottle neck. A desirable area of use of the conveyor apparatus according to the invention is receiving, holding and transporting upwardly open bottles which are preferably made from plastic material. The width of the respective U-shaped recess then approximately corresponds to the outside diameter of the bottle neck in question. It will be appreciated that a bottle then only needs to be pushed from the outside into the bottom of the U-shape in order to provide a good hold for the bottle there. Unloading is conversely equally expedient. The production of such a package carrier is inexpensive and technically surprisingly simple. A metal sheet or bar of a suitable configuration with double walls and stiffening rails can be easily produced and does not require any maintenance whatsoever apart from cleaning. Such a package carrier can be used in the above-described devices and transported over the various conveyor paths. Carriers, supports and rails mounted thereto can be provided at the narrow ends of a preferably bar-shaped sheet member so that the package carriers are supported with simple means along the first process plane and also along the second return plane and are preferably displaced with a sliding motion on support rails.
In that respect in accordance with the invention it is particularly advantageous if the drive device of the first conveyor in the first process plane has at least one thrust rod which extends in the first travel direction and which is pivotable and which can be pushed forward and back in the first travel direction and in the opposite direction thereto and on which are fixed at a spacing from each other advance projections which can be brought into engagement with locking grooves on the package carrier. It is precisely in the first process plane in which the packages have to be treated and transported in a hygienic fashion because inter alia this involves filling of the package, that simple and robust motion means should guarantee a reliable advance movement. The at least one thrust rod is such a conveyor means. Fixed to the thrust rod at a spacing from each other are advance projections which for example all protrude in a first direction radially from the thrust rod. If the thrust rod is pivoted about its own axis, those advance projections can then be pivoted from a rest position into such a position in which the advance projections engage into locking grooves on the package carrier, the locking grooves being arranged in just fitting oppositely disposed relationship. When then the thrust rod is moved a distance in the direction of its longitudinal direction, the package carrier is then also moved by the same amount. If thereafter the thrust rod is again pivoted through an angle which can be for example 90xc2x0 or 180xc2x0, the locking grooves then release the package carriers. The thrust rod can move back to the next package carriers, come into engagement therewith and then also push them on. When a plurality of advance projections are fixed to the thrust rod, then a plurality of package carriers can be moved at the same time. In the case of wider conveyor apparatuses, it is desirable in accordance with the invention to provide on each side, that is to say at the two oppositely disposed ends (wide sides) of the package carrier, a respective rod, that is to say in total two thrust rods in the apparatus. It is desirable if a single motor provides a synchronous for both thrust rods. One motor can provide for example for longitudinal displacement and the other for pivotal movement.
In the case of high-output machines each treatment station has a dual row of treatment devices which are arranged in transversely mutually juxtaposed relationship. If then for example a flushing operation is carried out on the interior of the package in one station, then the flushing operation is effected simultaneously for two (or a multiple of two) packages. If in the next treatment station the flushing substance is removed by drying, then two respective drying devices respectively provide for drying out the interior of the packages simultaneously in the next treatment station. This time-saving design configuration of the overall conveyor and filling machine involves double the number of tools in each treatment station. In the case of nozzles or the like this does not involve a high level of costs. If however consideration is given to the procedure for sealing and closing a package, the devices involved are nonetheless quite expensive if precise and in addition possibly also sterile sealing has to be effected. It would then be desirable and possible to provide only one row of sealing stations when the package carrier is firstly moved with the respective leading packages in the leading recesses into position under the sealing stations and thereafter the respective next packages in the trailing recesses of the same package carrier are moved into position under the same sealing stations. This means however that the conveyor apparatus must be capable of conveying the package carrier only by half a cycle distance. That is possible from the point of view of time, that is to say treatment in half the cycle time is possible, for the sealing operation is effected must faster than the operation of filling the package with a liquid.
Therefore according to the invention a particularly preferred embodiment is characterized in that fixed between two advance projections which project radially in the same direction from the thrust rod is an intermediate stroke projection projecting radially in another direction on the thrust rod, in such a way that each package carrier can be advanced in half the cycle time by half the cycle distance under a given treatment station.
The advantageous structure of the respective package carrier and the support thereof laterally on support rails on which it is slidingly displaced permit the individual package carriers to be decoupled from each other. The described simple conveyor means with the advance projections are capable of advancing the package carriers in each case by an entire cycle distance. If now in accordance with the last-described measure an intermediate stroke projection projects radially from the thrust rod between two advance projections at a different angle, other cycle distances with other cycle times are possible for the same package carrier. Therefore in one and the same process plane the package carriers can be conveyed by way of seven (or fewer) out of eight treatment stations in each case by an entire cycle distance and in one (or more) stations the package carrier can be conveyed twice by half the cycle distance, so that firstly the front row of the open and filled packages passes into a position under the row of sealing tools and in the next step still within the full cycle time (for the filling operation) the next rear row passes into a position under the sealing tools so that both rows of packages can be successively provided with sealed closures in the full cycle time.
A further advantage of the U-shaped recesses in the package carrier of the widths which are adapted to the bottle necks is that bottle bodies of a different format can be accommodated and transported by one and the same package carrier provided only that the outside dimensions of the bottle neck are the same. In many bottles of different formats, the neck dimensions are standardized and are of a fixed structure.
In contrast to the state of the art the package carriers according to the invention are not rigidly interlinked so that they can be flexibly staggered. Almost all package carriers for example can be moved into the first process plane and the arrangement cleaned at the other conveyor portions or almost all package carriers can be moved into the second return plane in order to clean the individual treatment stations from all sides. Portions of the overall conveyor according to the invention can therefore be run empty. The simple and practical way in which the package carriers are held on the carrier rails means that it is possible for them to be replaced in a very short time and using simple tools. That can be necessary under some circumstances for example upon a change in bottle or format.
Loading of the package carriers from both sides, in a preferred embodiment from the front and from the rear, permits loading and transporting of the packages at both sides, in a short time and in a space-saving fashion.